Ah, I love those people... They give me job security...
My personal favorite is if someone wants to do something in a document, they don't look for the proper Word style, they simply write another one because they're too lazy. And the next person does the same thing, often duplicating the efforts of the first.
And then, they merge two, three, or more documents, each with its own unique set of styles, into a single document... And they do so without flushing the old document's styles, which are immediately imported into the new document...
So now, instead of having one clean original document with with 30 or so styles, you've got the 42nd level of hell document with several HUNDRED styles and most of them either useless because they're not built correctly or they're duplicating multiple other styles.
Guh.
And most of them can get by with maybe three styles: Normal, Body Text, and Subparagraph1 (or Outline1)
I think another problem is that many (dare I say "most"?) companies and organizations don't have any standards established for this. They seem to assume that when they hire someone who can turn on a computer, that person
must already know how to use Word so no instruction, training, or guidance is necessary.
Many years ago I worked for a company that had a marketing director, who had his own "administrative assistant." She was a gorgeous blonde, and she had Peter absolutely snowed. One day he sent me a proposal he was working on and he asked me to edit it. When I started editing, the printed drafts would up with "headers" and "footers" scattered throughout the document. His administrative assistant had claimed on her resume, among other things, that she had been an instructor in word processing. But she didn't know how to create a header and footer so they automatically went at the top and bottom of each page. She was actually entering them manually each time the text scrolled to a new page.
I pointed out to Peter that his assistant was not what she seemed to be, and he became very defensive. So I just gave him the edited document and let him deal with the aftermath -- I didn't fix the headers and footers. "Not my job, mon."